Robot cleaner



FIG. 1 is a front perspective view of a robot cleaner showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left-side view thereof;

FIG. 5 is a right-side view thereof; and,

FIG. 6 is a top view thereof.

The broken lines in the figure show portions of the robot cleaner which form no part of the claimed design. 

CLAIM We claim the ornamental design for a robot cleaner, as shown and described. 